Removing acids from petroleum



Nov. 3, 1959 H. MYERS REMovING ACIDS FROM PETROLEUM Filed OCT.. '1, 1956llnitedy States Patent O REMoviNG ACIDS FRoM'PETnoLEUM Hugh L. Myers,Springfield, Pa., assignorto Sun Oil i Company, Philadelphia, Pa.,`acorporation of New 'Jersey v Application October 1, 1956 Serial No.613,311

8 Claims.v (Cl. 208-263) This invention relates to the removal ofnaphthenic acids and the obtaining of distillate oils from petroleumcrudes or reduced crudes.

In many instances, petroleum crudes contain naphthenic acids which it isdesirable to remove at some stage in the-refining of the crude. It hasbeen proposed previously'to remove the naphthenic acids by contactingthe crude in liquid phase with a basic material in the presence of anorganic solvent such as alcohol, to form salts of the basic materialwith the naphthenic'acids', which salts are extracted by the organicsolvent. It has also been proposed to remove naphthenic acids bydistilling crude or reduced crude to obtain vapors containing naphthenicacids, and contacting the vapors with a liquid alkaline treating agent,thereby to react the naphthenic acids with alkaline constituents' of thetreating agent. This type of operation is disclosed for example inUnited States application Serial No. 380,642, filed September 17, 1953,by Earl M. Honeycutt and Curtis C. Wallin, now Patent No. 27,770,580issued November 13, 1956.

It has now been found that results unexpectedly superior to thoseobtained with either of the above refining processes can be obtained bya process wherein crude or reduced crude is first contacted in liquidphase with a basic material in the presence of aqueous alcohol solution,the resulting crude or reduced crude then being distilled and the vaporsrefined by means of a liquid alkaline treating agent. Salts ofnaphthenic acids with basic material can be recovered from the organicsolvent used in the liquid phase treatment and also from the liquidalkaline material used in the vapor phase treatment. In one embodimentof the invention, superior results are obtained by employing a singlenaphthenic acid recovery operation for the naphthenate-containingproducts of both the liquid phase and the vapor phase treatment.

The liquid phase treatment preferably produces a crude or reduced crudeproduct having A.S.T.M. neutralization number, in mg. of KOH per gram,which is 0.1 to 0.9 times, and preferably 0.25 to 0.75 times, theneutralization number of the charge stock. It has been found that thebeneficially superior results according to the invention are obtainedwith such reduction in neutralization number, as compared to complete ormore nearly complete removal of acidity by either the liquid phasetreatment alone or the vapor phase treatment alone.v

Too nearly complete removal of acidity by the liquid phase treatmentgives inferior results to those obtained according 'to the invention inthat superior color stability is obtained in the distillation of thecrude or reduced crude when the vapors obtained in distillation arecontacted with a liquid alkaline material comprising alkali metalnaphthenates. If the removal of naphthenic acids is too nearly completein the liquid phase operation, the amountaof naphthenates present in thevapor phaseoperaltionwill not be suitable forobtaining distillateshaving good-color stability. The'naphthenates are beneficial in thevapor phase operation as color stability improvers and :Diritti i ICCpart to decomposition of alkali metal naphthenates at the hightemperatures (575 F. to 725 F.) involved in the l vapor phase operation,can be alleviated by using large amounts of liquid oil in the treatingagent, but it is desirable to minimize as much as possible the amount ofoil Vthus used.

The extent of removal of naphthenic acids in the liquid phase treatingoperation can be controlled by regulation of the amount of base employedand other conditions, in a manner within the ability of a person skilledin the art in the light of the disclosure in the present specification.The extent of removal is in any event less than the maximum that couldbe obtained.

The present invention provides an extent of removal of naphthenic acidsprior to the vapor phase treatment which enables thattreatment to beperformed without excessive oil requirements for the treating agent andalso without excessive decomposition of the organic materials' in thetreating agent and consequent plugging up of thel vapor phase treatingzone with solid carbonaceous decom-l position products. The process ofthe invention also provides stable lubricating oil distillates andpermits the refining of highly acidic crudes with the aforementionedbenefits.

It is within the scope of the invention to remove morev than 0.9 'timesthe original acidity of the charge in the' liquid phase operation, andblend back naphthenates in amount such that the alkali metalnaphthenates introduced into the liquid alkaline material corresponds to10 to 90 weight percent of the naphthenic acids in the charge stock.Thus, forexample, if all of the naphthenic acids were removed as alkalimetal naphthenates in the liquid phase operation, l0 to 90 percent ofthe resulting naphthenates' l ber within the approximate range from 1.5to 6 mg. of'

and alcohol soluble, can be employed in the liquid phase could beintroduced into the liquid alkaline material in the vapor phaseoperation.

Preferably, the liquid alkaline material in the vapor phase operationcontains alkali metal hydroxide as well as alkali metal naphthenates,though in some cases the" latter is sufficient. y

The `invention is particularly beneficial as applied to? crudes orreduced crudes which have particularly high acidity, as indicated forexample by neutralization num- KOH per gram. Preferably, in suchinstances, the liquid phase` treatment reduces the neutralizationnumberfto Within the approximate range from,0.5 to 3 mg. of KOH' pergram, and the subsequent vapor phase treating operation'reduces theneutralization number to within the; approximate range from 0 to 0.5 mg.of KOH per gram.. The basic material employed in the liquid phase treat'lng operation is preferably used in an amount within the approximaterange from 0.2 to 2.0 millimoles per volumes of charge stock per unit ofneutralization num. ber of the charge stock in nig. of KOH per gram.Theamount of basic material, otherwise expressed, is prefer-f ablywithin the approximate range from 0.1 to 2.0 weight` percent based oncharge stock.

Any suitable basic material, which-is water soluble,

treating operation. vExamples of suitable basic ID3- terlals tare'alkalimetal hydroxdes such as sodium hy-z droxide, potasslum hydroxide,i etct,ammonia, organic:

nitrogen bases Such as alkanol amines; ethnolamie'i ethanolamine,dimethyl ethanolamine, etc. The organic solvent vemployed in the liquidphase treating operation is preferably a lower alkanol containing 1 to 3carbon atoms, egg. methanol, ethanol, isopropanol, although other lowmolecular weight oxygen-containing organic solvents, e.g. acetone,methyl ethyl ketone, can also be employed.

The organic solvent is employed as an equeous solution havingconcentration preferably within the approximate range from ,30 to 50weight percent, and more .preferably 35 to 45 weight percent.` Theamount of basic material used in the liquid phase treating operation ispreferably within the approximate range from 0.1 to 5 'weight percent,more preferably l to 3 weight percent,

based lon the aqueous solution of organic solvent.

Ii' desir-ed, a saturated hydrocarbon diluent, c.g. pe-

t'roleum naphtha, aviation alkylate, etc., having an average number ofcarbon atoms within the approximate range from 5 to l0, can be employedin the liquid phase treating operation, for example in an amountequivalent to 50 to 100 volume percent based on charge. The liquid phasetreating operation is preferably carfied out at a temperature within theapproximate range from 50 to 200 F., and at atmospheric pressure,although higher pressures can be employed if desired.

In one embodiment of the process according to the invention,-thesolutionof naphthenate salts in organic vsolvent which is obtained inthe liquid phase treating operation is acidied, for example withsulfuric acid,

to liberate naphthenic acids, which can be separated from the organicsolvent by stratification, the separated organic solvent then beingavailable for re-use in the` liquid phase treating operation.

Alternatively, the solution of naphthenate salts in organic solventobtained in the liquid phase treating operation can be distilled toobtain aqueous alcohol as distillate and a concentrated solution ofnaphthenate salts in waterras residue. The distillation is preferablyconducted in such a manner as to obtain in thel residue an -amount ofalcohol, e.g. l to l0 volume percent (anhydrous basis) -based on thenaphthenate salts. VIn this way, a more Huid residue is obtained,facilitating further handling. The residue obtained in the distillationpreferably 4contains 30 to 60 volume percent of naphthenate salts basedon total residue.

Q ASome .lower molecular weight hydrocarbons, e.g. in the gasolineboiling range, which are extracted from the crude or reduced crude inthe liquid phase treating operation, are distilled over with the aqueousalcohol, in a distillation as described in the preceding paragraph, andsuch hydrocarbons can be separated by stratification from the aqueousalcohol, thus recovering these hydrocarbons as aproduct of the process.

. The crude or reduced crude, which has been sub- `jected to the liquidphase treating operation, is distilled to obtain vapors containingnaphthenic acids, the vapors then being contacted with a liquid alkalinetreating agent. If desired, two distillations can be performed, thefirst t0 remove lower boiling fractions such as gasoline and gas oil,and the second constituting a redistillation under vacuum of the residueto obtain lubricating oil distillates. Where a reduced crude is employedas the original charge stock, the vacuum distillation alone is generallysufficient.

'Where an entire crude is used as the original charge stock to theliquid phase treatment, a subsequent atmospheric pressure distillationin the absence of added alkali anda vacuum Ydistillation in the presenceof added alkali produces satisfactory results in the event that theliquid phase vtreatment removes the lower molecular l Weight naphthenicacids which would otherwise be removed in theatmospheric pressuredistillation. The color and color stability of distillates produced intheV atmospheric .pressure distillation `is in some instancesnotagproblem, so thatalkali can 'be dispensed with not 2,911,360 f 'Y N 4needed for neutralization of naphthenic acids in the vapors.

In the vacuum distillation, the charge stock is preferably heated to atemperature of from about 650 F. to 750 F. and introduced into a ashzone maintained at 25 to 100 mm. of Hg absolute. The contacting withliquid alkaline treating agent is preferably performed in a treatingsection above the flash zone and containing a plurality of distillationtrays, the liquid alkaline treating agent passing downwardly from trayto tray, counter-A current to the rising vapors. The liquid temperatureon the lowest tray of the treating section is preferably within theapproximate range from 575 F. to 725 F., andA more preferably 625 F. to675 F.

The liquid alkaline treating agent removed from the lowest tray ispreferably recycled in part to an upper tray of the treating section,the remainder of the removed treating agent being subjected toextraction with aqueous alcohol in order to remove naphthenate saltscontained in the treating agent. The treating agent removed frorn thelowest tray generally contains liquid oil, e.g to 95%, and this oil canif desired be recycled to the treating section after extraction ofnaphthenate salts therefrom. However, such recycle is frequently notnecessary because of the lower Oil requirements for the treating agentin the process according to the invention.

Fresh basic material, e.g. alkali metal hydroxide, is introduced intothe treating section in an amount sufficient to provide the desiredremoval of naphthenic acids from the vapors, andthe necessary excess forobtaining stable lubricating oil distillates. The amount is pre-ferablywithin the'approximate range from 0.2 to 2.0 millif molles per volumesoriginal charge stock vper unit `of neutralization number of theoriginal charge stock `in mg. of KOI-I per gram. in the event that morethan one distillation involving treatment of vapors with alkali `isperformed, the total amount of base employed in such distillations ispreferably within the -range stated in this paragraph.

After treatment with the liquid alkaline material, the vapors aresubjected to rectification in a rectification ,section above thetreating section in the distillation tower. The distillates obtainedgenerally have neutralization number which is less than 0.5 times theneutralization number of the crude'or reduced crude after the liquidphase treating operation. Preferably, the distillates ob,- taincd areneutral, and it has been found that the process according to theinvention is capable of providing such neutral distillates.

The invention will be further described with reference to the attacheddrawing, which is a schematic flow-sheet of one embodiment of theprocess according to the inven tion. Referring to the drawing, crude oilhaving neutralization number of about 2.3 mg. of KOH per-gram isintroduced into extraction zone 11. A basic material, e.g. 50 B. aqueouscaustic soda, is introducedinto'zone 11 through line 12.. An aqueoussolution of an Organic solvent, e.g. isopropanol, is introduced intozone Y11 through line 13. Suitable agitation means are provided toobtain intimate contacting between the crude and the aqueous treatingagent. The treatment is conducted .at any suitable temperature, forexample room temperature.

The treated crude is removed through line 14. The neutralization numberof the treated crude is for example about one mg. of KOH per gram.

An aqueous alcoholic solution of Vsodium naphthenates is separated fromthe treated crude by stratification and withdrawn through line 15. Inone suitable manner of operation, the solution is passed through line 16into alcohol recovery zone 17, wherein the solution is subjected todistillation to obtain an aqueous alcohol distillate which is removedthrough line 18. This distillate contains-some lower boilinghydrocarbons, e.g. gasoline hydrocarbons, and 1s introduced intogasoline recovery zone 19. In zone 19 the lower boiling hydrocarbons areseparated from the laqueous alcohol by stratification and removedthrough line 20. The aqueous alcohol is recycled through line 13 toYzone 11.

The residue obtained in the distillation in A,zone 17 is a concentratedsolution of sodium naphthenates in water, and also contains a smallamount of alcohol in order to make the solution suiliciently uid to bereadily handled by ordinary pumping and conveying equipment. Freshalcohol is introduced into zone 11 through line 23 to replace thealcohol withdrawn through line 22. The residue from the distillation inzone 17 is introduced into soap recovery zone 24, which willpbe morefully described subsequently.

Treated crude from zone 11, after a suitable conventional desaltingoperation if desired, is introduced intozone 30 wherein it is distilledat atmospheric pressure. The evolved vapors can be contacted with aliquid phase treating agent containing alkali, e.g. sodium hydroxide,introduced through line 31, although as pointed out previously suchcontacting with alkali can be dispensed with in some instances. Ifdesired, at least a portion of the treating agent removed, assubsequently described from zone 35 through line 38 can be introducedthrough means not shown into zone 30 in place of fresh alkali asindicated at line 31. The vapors, after Contact with alkali asdescribed, are fractionated to obtain distillates as iny dicated at line32. Any'aqueous alcohol which is asso-` ciated with the hydrocarbons inthe distillates can be separated therefrom by means not shown andintroduced into alcohol recovery zone 17. The residue from thedistillation is removed through line 33. The liquid alkaline treatingagent containing sodium naphthenates formed by reaction of sodiumhydroxide with naphthenic acids obtained n the vapors, is withdrawnthrough line 34 and introduced through line 41 into soap recovery zone24.

The residue removed through line 33 contains hydrocarbons in thelubricating oil boiling range and also containsk naphthenic acidsboiling in the same range. The naphthenic acids removed in zone 30, ifany, are lower molecularfweight acids boiling in the naphtha and gas oilranges. The-residue isintroduced into zone 35 where it is subjected todistillation. The evolved vapors are contacted with a liquid alkalinetreating agent containing alkali, e.g. sodium hydroxide, introducedthrough line 36. Lubricating oil distillates obtained from the treatedvapors are removed through line 37. The liquid alkaline treating agentcontaining sodium naphthenates formed by reaction of sodium hydroxidewith naphthenic acids in the vapors, is withdrawn through line 38 andintroduced through line 41 into soap recovery zone 24. Residue from thedistillation is removed through line 39.

The naphthenate-containing materials introduced into zone 24 throughlines 22 and 41 are contacted in zone 24 with an LAaqueous solution of alower alkanol, in the presencenoff-ay hydrocarbon diluent for the highmolecular weight 'hydrocarbons introduced into zone 24 through lines 34and 38. The alcohol and diluent, e.g. petroleum naphtha, aviationalkylate, etc., are introduced through zone 24 as indicated by line 42.Upon intimate contacting, the naphthenates are dissolved in the aqueousalcohol phase, and upon separation of layers, this phase is removedthrough line 43, and is suitably contacted with a strong acid such assulfuric acid to liberate naphthenic acids from the naphthenates. Uponseparation of layers,

the recovered aqueous alcohol is available for re-use, and

the naphthenic acids are recovered as a product of the process. Thenaphtha solution of oil, which is obtained in zone 24 upon separation oflayers, can be recycled, after stripping naphtha therefrom, throughmeans not shown into the treating section of zone 35. Alternatively, theoil can be hydrorefned to upgrade it to heavy lubricating oil.

The aqueous alcoholic solution of naphthenates, removed through line 15from zone 11 can, instead of being in the material introduced throughline 40 is advantageously used as a diluent, partially or completelyreplacing diluent fromv an external source. l

The following example illustrates the invention:

yA process is Vcarried out according to the procedure indicated in thedrawing. 200 volumes per hour of a blend of 20 percent Quiriquire crudeand 80 percent Coastal crude, the blend having A.P.L gravity of about 24and acid number of 2.3 mg. of KOH per gram, largely,

Iattributable to naphthenic acids, are introduced intoy Vextraction zone11. 40 volumes per hour of 40% aqueous isopropanol and 0.4 volume perhour of 50 B. caustic soda are also introduced into zone 11.

indicating extraction of about percent of the acid content of theoriginal crude; The extraction in zone 11 is carried out at atmosphericpressure and room temperature.

5 'volumes per hour of water and l0 volumes per hour of 40% isopropanoland the treated crude from zone 11 .are introduced into conventionaldesalting equipment.

They treated crude, after desalting, is topped in zone 30 to obtain aresidue (about 2O A.P.I.) constituting about 55-65 percent of the crude.The residue is heated to about 650.F. bymeans not shown and flashed inzone 35 at an absolute pressureof about 70 mm. of Hg. Residuehaving,A.P.I. gravity of about 12 is withdrawn through line 39. Thevapors pass through a caustic treating zone wherein they are contactedwith a liquid alkalinetreating agent having, on the lowest tray of thetreating Vzone,-the following composition: oil, volume percent; sodiumnaphthenates, 8 volume percent; sodium hydroxide, 2 volume percent. Thistreating agent is in part recycled at 70 volumes per hour to an upperportion of the treating yzone and in part introduced at 7 volumes perhourthrough line 38 into zone 24. 50

B. caustic sodal at 0.2 volume per hour is introduced through line 36 toreplace the `treating agent removed through line 38.k Distillates havingacid number of zero are .obtained by rectication of the treatedvaporsrrin a rectification zonel abovethe treating zone.

The alcoholicl soap removed-from zone 11 through lineV 15 containsabout40 volumes per hour of alcohol and 2.4 volumes per hour of sodiumnaphthenates. This material is introduced into zone 17. The residueremoved rfrom zone 17 through line 22 contains on an hourly basis, about6 volumes of water, 2.4 volumes of sodium 7 naphthenates, and 0.1 volumeof alcohol. 0.1 volume per hour of alcohol is added through line 23 asmake-up.

The removal of about 85 percent of the naphthenic acids in the originalcrude by alcoholic alkali treatment reduces by about 85 percent theamount of oil required in the treating agent in the vapor phasetreatment, thus increasing the yield of lubricating oil in the vacuumdistillation over that which would be obtained if the original crudewere charged to the distillation with alkali. The introduction into thevapor phase operation of naphthenates corresponding to l5 percent `ofthe naphthenic acids in the original crude permits obtaining lubricatingoil distillates having superior color stability to that obtained indistillation in the absence of naphthenates. The presence of alkalimetal hydroxide is also helpful in obtaining good color stability,though in some cases it may not be necessary, for example wheresubstantially all of the naphthenic acids have been removed in theliquid phase operation, and sucient naphthenates The crude removedthrough line 14 has lacid number of about 0.3,v

aref-added in the vapor phase operation. to provide satis-V factorycolor stability in the distillates.l

It is not definitely known by what mechanism the'alkalimetalvnaphthenates present in the vapor phase treatment prevent the poorcolor stability which the distillates exhibit when naphthenates `areabsent. The mechanism does not involve reaction with inorganic acidspresent in the hydrocarbon charge to the vapor phase treatment, sincesuch acids are substantially completely removed inthe liquid phasetreatment'. Frequently, the amount of inorganic acidity in the charge tothe liquid phase treatment is only a small proportion of the totalacidity. In any event, the reduction in acidity -as `a result of theliquid phase treatment is greater than `the original inorganic acidity,yand is preferably sufficient to remove in addition at least 10 percentof the acidity attributable to naphthenic acids.

InV place of the alkali metal hydroxide of the preceding example,various 4other basic materials as previously mentioned can be employedin the liquid phase treatment with generally similar results. Some ofthese basic mate-l -rials provide advantages in some instances. Thus,am-

- monia for example is advantageous in that ammonium naphthenates whichare formed can be present in small amountin the hydrocarbon products ofthe liquid phase treatment without producing'detrimental results.Ammonium naphthenates decompose under the conditions of the'vaporphasetreatment to form ammonia and naphthenic acids, so that nosubstantial amount of naph-` tbenates remains in the residue from thevapor phase treatment. In this embodiment, the liquid` alkaline treatingagent inthe vapor phase treatment should contain alkali metal hydroxideto react with the naphthenic acids formed by decomposition of ammoniumnaphthenates.

The invention claimed is:

l'. Process `for refiningv petroleum which comprises: contacting inliquid phase a charge stock containing naphthenic acids and selectedfrom the group consisting of crude petroleum and reduced crude petroleumwith a 30 to 50 Weight percent aqueous solution of a lower alkanol in*the. presence of 0.2 to2 millimoles of an alkali metal hydroxide per 100volumes of said charge stock per unit of neutralization number of saidchargestock in mg. of KOI-Iper gram, the amount of said solutionY being10 to 60 volume percent based on said charge, thereby to obtain` aproduct having neutralization number which is 0.1 to 0.9 times the acidnumber of said charge stock; vaporizing a portion of theproductrt'oobtain vapors containing naphthenic acids; contacting thevapors with a liquid alkaline treating agentA containing alkali metalhydroxide thereby to react said naphthenic acids with alkali metalhydroxide;' and reco-vering distillates from the vapors thus treated.

2'. Process according to claim 1 wherein liquid' alkaline treatingagent, after contact with said vapors, is contacted with an aqueoussolution of a lower alkanol, thereby to extract alkali metalnaphthenates from the treating agent.

3; Process according to claim 2 wherein' alkanol solution from theliquid phase contacting, which solution contains alkali metalnaphthenates, is'contacted with said liquid alkaline treating agent,after contact with said vapors, thereby to extract alkali metalnaphthenates from the treating agent and enrich the alkanol solution inalkali metal naphthenates, and wherein the alkanol solution enriched inalkali metal naphthenates'V is separated from the hydrocarbon containedin said treatingagent.

4. Process according to claim 1 wherein alkanol sol-ution from theliquid phase contacting, which solution contains alkali lmetalnaphthenates, is distilled to recover an aqueous alkanol distillate andas residue a concentrated aikali metal naphthenate solution containing asmall amount of alkanol, and said residue and said liquid alkalinetreating agent after contact with said vapors, are contacted with anaqueous solution of a lower alkanol, there-v by to extract alkali metalnaphthenates from the treating agent and the residue y y Y, Y

5. Process accordinglto claim 4 wherein hydrocarbons distilled with theaqueous alkanol are separated from` said distillate.

y 6. Process for refining petroleum which comprises: coritacting inliquid phase a charge stock containing naphthenic acids and selectedfrom the group consisting of crude petroleum and reduced crude petroleumwith an aqueous solution of an oxygen-containing organic solvent',containing a base reactive with naphthenic acids, thereby to react atleast l0 weight percent of said naphthenic acids with the base;separating the treated petroleum phase from the aqueous phase containingthe reaction products of naphthenic acids with basevaporizing a portionof thetreated petroleum; contactingthe vapors with a liquid alkalinetreating agent containing suicient alkali to reactl with any naphthenicacids in the vapors and containing alkali metal naphthenates in amountcorresponding to l0 to Weight percent of the naphthenic acids in thecharge stock; and recovering distillates from the vapors thus treated.

7. Process according to claim 6 wherein: saidv charge stock hasneutralization number within the approximate range from 1.5 to 6 mg. ofKOH per gram; the product References Cited in the le of this patentUNITED STATES PATENTS Y 2,658,027 Hooverv Y Nov. 3,19'53 Fierce et al.Nov. 6, 1956

1. PROCESS FOR REFINING PETROLEUM WHICH COMPRISES: CONTACTING IN LIQUIDPHASE A CHARGE STOCK CONTAINING NAPHTHENIC ACIDS AND SELECTED FROM THEGROUP CONSISTING OF CRUDE PETROLEUM AND REDUCED CRUDE PETROLEUM WITH A30 TO 50 WEIGHT PERCENT AQUEOUS SOLUTION OF A LOWER ALKANOL IN THEPRESENCE OF 0.2 TO 2 MILLIMOLES OF AN ALKALI METAL HYDROXIDE PER 100VOLUMES OF SAID CHARGE STOCK PER UNIT OF NEUTRALIZATION NUMBER OF SAIDCHARGE STOCK IN MG. OF KOH PER GRAM, THE AMOUNT OF SAID SOLUTION BEING10 TO 60 VOLUME PERCENT BASED ON SAID CHARGE, THEREBY TO OBTAIN APRODUCT HAVING NEUTRALIZATION NUMBER WHICH IS 0.1 TO 0.9 TIMES THE ACIDNUMBER OF SAID CHARGE STOCK; VAPORIZING A PORTION OF THE PRODUCT TOOBTAIN VAPORS CONTAINING NAPHTHENIC ACIDS; CONTACTING THE VAPORS WITH ALIQUID ALKALINE TREATING AGENT CONTAINIG ALKALI METAL HYDROXIDE THEREBYTO REACT SAID NAPTHENIC ACIDS WITH ALKALI METAL HYDROXIDE; ANDRECOVERING DISTILLATES FROM THE VAPORS THUS TREATED.